std::rewind (3) - Linux Manuals

std::rewind: std::rewind

NAME

std::rewind - std::rewind

Synopsis

Defined in header <cstdio>
void rewind( std::FILE* stream );

Moves the file position indicator to the beginning of the given file stream.
The function is equivalent to std::fseek(stream, 0, SEEK_SET);, except that end-of-file and error indicators are cleared.
The function drops any effects from previous calls to ungetc.

Parameters

stream - file stream to modify

Return value

(none)

Example

// Run this code

  #include <cstdio>

  int main()
  {
      std::FILE *f;
      char ch;
      char str[20];

      f = std::fopen("file.txt", "w");
      for (ch = '0'; ch <= '9'; ch++) {
          std::fputc(ch, f);
      }
      std::fclose(f);

      std::FILE* f2 = std::fopen("file.txt", "r");
      unsigned int size = std::fread(str, 1, 10, f2);
      std::puts(str);
      std::printf("\n%u\n",size);

      std::rewind(f2);
      unsigned int size2 = std::fread(str, 1, 10, f2);
      std::puts(str);
      std::printf("\n%u",size2);
      std::fclose(f2);
  }